1. Field of the Invention
The invention relates to a modified glad hand and gasket combination for forming an air tight connection between two glad hand coupling members on the ends of air brake hoses for railroad cars. Specifically, the invention relates to an improved glad hand having an improved gasket shape for better alignment and more effective sealing, which in turn reduces unintended decoupling incidents. More particularly, the invention relates to an improved gasket having an increased entrance angle and an increased sealing surface for providing better alignment and sealing during coupling.
2. Description of Related Art
In a conventional railroad train braking system, each railway vehicle is provided with a brake pipe line which extends along the length of the vehicle. The pipe line is connected to the brake cylinders via reservoirs and valves. Each end of the brake pipe is coupled to a “glad hand” connector by an angle or stop cock and a flexible hose. The glad hand connectors are fastened together to form a continuous pipe line stretching from the head locomotive to the last train car. Each flexible hose has a glad hand, acting as a coupling member, at each end for detachably connecting the hose sections of adjacent cars together when joining additional individual railroad cars.
Glad hands are joined by pulling the hoses from adjacent cars upward, pushing the sealing gaskets on the glad hands at the end of each hose into aligned and abutting relationship, and then rotating the coupling members downward which interengages mating flanges and lugs extending from the coupling members. This coupling results in a sealed fluid passage between air hoses on adjacent railroad cars, which maintains the brakes of all of the individual cars in an “off” position. If there is a significant reduction in air pressure within the hose lines, such as in the case of derailment or separation of cars, the brakes move into the “on” position. Any accidental separation of the coupling between two air hoses causes an emergency braking of the train cars and resulting disruption to train service. It is important to avoid such stoppages for both safety and economy.
Couplings between the air hoses are often difficult to properly align. If they are not properly aligned, there will not be an air tight seal, as there is supposed to be, which leads to leaks or a failed seal. Even when the couplings are properly aligned, the seal created by the gaskets must be able to withstand upwards of 90 p.s.i. during operation. It is a well-known problem that the current gasket designs sometimes fail to maintain the pneumatic pressure, which results in leaks either slowly or rapidly leading to emergency brake activation. There is a prevalent problem regarding gasket alignment between the two adjacent coupling members. Such alignment is crucial in obtaining a proper seal to withstand the pressure during operation.
The components of the railroad train are designed and manufactured to meet the requirements of the Association of American Railroads (“AAR”) and are generally similar. Two sections of the “AAR Manual of Standards and Recommended Practices; Brakes and Brake Equipment” set standards for glad hand connectors and sealing gaskets: Standard S-456 and Specification M-602. Standard S-456 sets forth the dimensions for the standard gasket in FIG. 6.1, depicting a gasket with a surface area of 0.659 in2. Specification M-602 sets forth additional dimensions for the standard gasket in FIG. 4.1, and further illustrates an angled edge at an angle of 45° with the center line of the gasket.
U.S. Pat. No. 6,290,238 discloses a gasket for use in detachably connecting two similar coupling members on the ends of air brake hoses for railroad cars. The gasket disclosed therein provides a ramped entrance angle, two outward projections, and a wide sealing surface for providing alignment and sealing. However, in that design, a channel is formed in the gasket, which engages a protrusion on the glad hand. The thin portion of the gasket outside the protrusion bears against the glad hand fitting and is easily worn and damaged.
Despite the progress that has been made in gaskets design, the prior art does not provide an adequate solution to the problem of misalignment of coupled air brake hoses and improper sealing.
The invention disclosed herein addresses the need for a glad hand and gasket combination having a self-aligning feature and an expanded sealing surface to improve the reliability of end hose coupling.